Context.maskSurface

void maskSurface(cairo.surface.Surface surface, double surfaceX, double surfaceY)

A drawing operator that paints the current source using the alpha channel of surface as a mask. (Opaque areas of surface are painted with the source, transparent areas are not painted.)

Parameters

surfacea #cairo_surface_t
surfaceXX coordinate at which to place the origin of surface
surfaceYY coordinate at which to place the origin of surface